launch_tests: global var: to upper

+ added ANDROID_TRACE_OUT + TCPDUMP_PID
launch_tests: Remove previous traces at the beginning
launch_tests: uitests: removed iface

(no longer needed, tcpdump has to be launched by this script)
launch_tests: launch tcpdump + sshproxy before tests

Before each uitest, the server has to start a capture and the device too.
Then we can start to use the proxy, launch the uitest, kill the app, stop the proxy, stop capturing on the device and on the server

This commit also changes the output dir of .pcap file in the device
launch_tests: adb_shell: catch the errno

Used Popen.

TODO: timeout
launch_tests: Timeout of 3 minutes
launch_tests: adb_shell, support uiautomator
launch_tests: support timeout
launch_tests: red -> RED
launch_tests: catch FAILURE if uiautomator
backup_traces: progress + without -e